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Kaur A, Kaur N, Madhukar M. Assessment of Corrected QT Interval and QT Dispersion in Patients with Uncomplicated Metabolic Syndrome. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2023; 15:S1097-S1100. [PMID: 37693981 PMCID: PMC10485503 DOI: 10.4103/jpbs.jpbs_207_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 09/12/2023] Open
Abstract
Aim Metabolic syndrome (MS) itself has become a new entity being a constellation of physiological, biochemical, metabolic, and clinical factors that have been related to an increased risk of cardiovascular diseases, type 2 diabetes mellitus (T2DM), and morbidity and mortality. The burden of MS is increasing all over the world with the current prevalence being 30%. The QT interval and QT dispersion (QTd) have been long associated with ventricular arrhythmia and sudden cardiac deaths. The association between QT and diabetes and healthy subjects has been clearly studied, but the association between QT and uncomplicated MS has not been very well defined. Methods A total of 400 patients visiting the medicine clinics were assessed for blood pressure, anthropometric measurements, fasting serum lipid profile, FBS, and electrocardiogram (ECG). The patients diagnosed with uncomplicated MS as per the International Diabetic Federation (IDF) criteria were included in the study. QT interval in the ECG was recorded, and the relationship between various parameters of an uncomplicated MetS and the QT interval was recorded. Results Our study revealed more females with uncomplicated MS as compared to males and increasing burden as age progressed. Body mass index (BMI), waist circumference (WC), hip circumference (HC), WHP, systolic blood pressure (SBP), Diastolic blood pressure (DBP), Fasting blood sugar (FBS), serum cholesterol, triglyceride (TG), and low-density lipoprotein (LDL) levels were positively correlated with QT values. Conclusion QT interval, a strong predictor of malignant ventricular arrhythmias and sudden cardiac deaths, is associated with uncomplicated MS.
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Affiliation(s)
- Amandeep Kaur
- Department of General Medicine, All India Institute of Medical Sciences, Bathinda, Punjab, India
| | - Navdeep Kaur
- Department of Radiodiagnosis, All India Institute of Medical Sciences, Bathinda, Punjab, India
| | - Mohit Madhukar
- Department of Pathology, District Hospital, Bathinda, Punjab, India
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2
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Kulecki M, Naskret D, Kaminski M, Kasprzak D, Lachowski P, Klause D, Kozlowska M, Flotynska J, Uruska A, Zozulinska-Ziolkiewicz D. Arterial stiffness and the non-dipping pattern in type 1 diabetes males with and without erectile dysfunction. Sci Rep 2023; 13:7265. [PMID: 37142663 PMCID: PMC10160017 DOI: 10.1038/s41598-023-33315-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 04/11/2023] [Indexed: 05/06/2023] Open
Abstract
Arterial stiffness (AS) and non-dipping pattern are early predictors of cardiovascular diseases but are not used in clinical practice. We aimed to assess if AS and the non-dipping pattern are more prevalent in the erectile dysfunction (ED) group than in the non-ED group among subjects with type 1 diabetes (T1DM). The study group consisted of adults with T1DM. Aortic pulse wave velocity (PWV Ao)-a marker of increased AS, central systolic blood pressure, and heart rate (HR) were measured with a brachial oscillometric device (Arteriograph 24). Erectile dysfunction (ED) was assessed by the International Index of Erectile Function-5. A comparison between the groups with and without ED was performed. Of 34 investigated men with T1DM, 12 (35.3%) suffered from ED. The group with ED had higher mean 24 h HR (77.7 [73.7-86.5] vs 69.9 [64.0-76.8]/min; p = 0.04, nighttime PWV Ao (8.1 [6.8-8.5] vs 6.8 [6.1-7.5] m/s; p = 0.015) and prevalence of non-dipping SBP Ao pattern (11 [91.7] vs 12 [54.5]%; p = 0.027) than individuals without ED. The presence of ED detected a central non-dipping pattern with a sensitivity of 47.8% and a specificity of 90.9%. The central non-dipping pattern was more prevalent and the nighttime PWV was higher in T1DM subjects with ED than in those without ED.
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Affiliation(s)
- Michał Kulecki
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland.
| | - Dariusz Naskret
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Mikolaj Kaminski
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Dominika Kasprzak
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Pawel Lachowski
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Daria Klause
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Maria Kozlowska
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Justyna Flotynska
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Aleksandra Uruska
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
| | - Dorota Zozulinska-Ziolkiewicz
- Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, ul. Mickiewicza 2, 60-834, Poznań, Poland
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3
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Abraham MB, Karges B, Dovc K, Naranjo D, Arbelaez AM, Mbogo J, Javelikar G, Jones TW, Mahmud FH. ISPAD Clinical Practice Consensus Guidelines 2022: Assessment and management of hypoglycemia in children and adolescents with diabetes. Pediatr Diabetes 2022; 23:1322-1340. [PMID: 36537534 PMCID: PMC10107518 DOI: 10.1111/pedi.13443] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 12/24/2022] Open
Affiliation(s)
- Mary B Abraham
- Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Australia.,Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia.,Discipline of Pediatrics, Medical School, The University of Western Australia, Perth, Australia
| | - Beate Karges
- Division of Endocrinology and Diabetes, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Klemen Dovc
- Department of Pediatric Endocrinology, Diabetes and Metabolic Diseases, UMC - University Children's Hospital, Ljubljana, Slovenia, and Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Diana Naranjo
- Division of Endocrinology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Ana Maria Arbelaez
- Division of Endocrinology and Diabetes, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joyce Mbogo
- Department of Pediatric and Child Health, Aga Khan University Hospital, Nairobi, Kenya
| | - Ganesh Javelikar
- Department of Endocrinology and Diabetes, Max Super Speciality Hospital, New Delhi, India
| | - Timothy W Jones
- Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Australia.,Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia.,Discipline of Pediatrics, Medical School, The University of Western Australia, Perth, Australia
| | - Farid H Mahmud
- Division of Endocrinology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Canada
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4
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Lubberding AF, Juhl CR, Skovhøj EZ, Kanters JK, Mandrup‐Poulsen T, Torekov SS. Celebrities in the heart, strangers in the pancreatic beta cell: Voltage-gated potassium channels K v 7.1 and K v 11.1 bridge long QT syndrome with hyperinsulinaemia as well as type 2 diabetes. Acta Physiol (Oxf) 2022; 234:e13781. [PMID: 34990074 PMCID: PMC9286829 DOI: 10.1111/apha.13781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/20/2021] [Accepted: 01/02/2022] [Indexed: 12/13/2022]
Abstract
Voltage‐gated potassium (Kv) channels play an important role in the repolarization of a variety of excitable tissues, including in the cardiomyocyte and the pancreatic beta cell. Recently, individuals carrying loss‐of‐function (LoF) mutations in KCNQ1, encoding Kv7.1, and KCNH2 (hERG), encoding Kv11.1, were found to exhibit post‐prandial hyperinsulinaemia and episodes of hypoglycaemia. These LoF mutations also cause the cardiac disorder long QT syndrome (LQTS), which can be aggravated by hypoglycaemia. Interestingly, patients with LQTS also have a higher burden of diabetes compared to the background population, an apparent paradox in relation to the hyperinsulinaemic phenotype, and KCNQ1 has been identified as a type 2 diabetes risk gene. This review article summarizes the involvement of delayed rectifier K+ channels in pancreatic beta cell function, with emphasis on Kv7.1 and Kv11.1, using the cardiomyocyte for context. The functional and clinical consequences of LoF mutations and polymorphisms in these channels on blood glucose homeostasis are explored using evidence from pre‐clinical, clinical and genome‐wide association studies, thereby evaluating the link between LQTS, hyperinsulinaemia and type 2 diabetes.
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Affiliation(s)
- Anniek F. Lubberding
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Christian R. Juhl
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Emil Z. Skovhøj
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Jørgen K. Kanters
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Thomas Mandrup‐Poulsen
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Signe S. Torekov
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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5
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Tommerdahl KL, Baumgartner K, Schäfer M, Bjornstad P, Melena I, Hegemann S, Baumgartner AD, Pyle L, Cree-Green M, Truong U, Browne L, Regensteiner JG, Reusch JEB, Nadeau KJ. Impact of Obesity on Measures of Cardiovascular and Kidney Health in Youth With Type 1 Diabetes as Compared With Youth With Type 2 Diabetes. Diabetes Care 2021; 44:795-803. [PMID: 33402367 PMCID: PMC7896261 DOI: 10.2337/dc20-1879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/23/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Insulin resistance and obesity are independently associated with type 1 diabetes (T1D) and are known risk factors for cardiovascular and kidney diseases, the leading causes of death in T1D. We evaluated the effect of BMI on cardiovascular and kidney outcomes in youth with T1D versus control youth with normal weight or obesity and youth with type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS Pubertal youth (n = 284) aged 12-21 years underwent assessments of resting heart rate (RHR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), leptin, hs-CRP, adiponectin, ratio of urine albumin to creatinine, and estimated glomerular filtration rate. Participants with T1D underwent bicycle ergometry for VO2peak, monitoring for peripheral brachial artery distensibility (BAD), endothelial function testing for reactive hyperemic index, and aortic MRI for central arterial stiffness or shear. RESULTS In adolescents with T1D, RHR, SBP, DBP, mean arterial pressure, leptin, hs-CRP, and hypertension prevalence were significantly higher, and BAD, descending aorta pulse wave velocity, and VO2peak lower with an obese versus normal BMI. Although hypertension prevalence and RHR were highest in obese adolescents with T1D and adiponectin lowest in youth with T2D, other measures were similar between obese adolescents with T1D and those with T2D. CONCLUSIONS Obesity, now increasingly prevalent in people with T1D, correlates with a less favorable cardiovascular and kidney risk profile, nearly approximating the phenotype of youth with T2D. Focused lifestyle management in youth-onset T1D is critically needed to reduce cardiovascular risk.
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Affiliation(s)
- Kalie L Tommerdahl
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Barbara Davis Center for Diabetes, University of Colorado School of Medicine, Aurora, CO.,Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Karl Baumgartner
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Michal Schäfer
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Petter Bjornstad
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Isabella Melena
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Shannon Hegemann
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Amy D Baumgartner
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Laura Pyle
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO
| | - Melanie Cree-Green
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO
| | - Uyen Truong
- Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO.,Department of Pediatrics, Section of Cardiology, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, VA
| | - Lorna Browne
- Department of Pediatrics, Section of Radiology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Judith G Regensteiner
- Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Medicine, Divisions of General Internal Medicine and Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jane E B Reusch
- Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO.,Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO
| | - Kristen J Nadeau
- Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, CO .,Center for Women's Health Research, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, CO
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6
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Ozturk N, Uslu S, Ozdemir S. Diabetes-induced changes in cardiac voltage-gated ion channels. World J Diabetes 2021; 12:1-18. [PMID: 33520105 PMCID: PMC7807254 DOI: 10.4239/wjd.v12.i1.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus affects the heart through various mechanisms such as microvascular defects, metabolic abnormalities, autonomic dysfunction and incompatible immune response. Furthermore, it can also cause functional and structural changes in the myocardium by a disease known as diabetic cardiomyopathy (DCM) in the absence of coronary artery disease. As DCM progresses it causes electrical remodeling of the heart, left ventricular dysfunction and heart failure. Electrophysiological changes in the diabetic heart contribute significantly to the incidence of arrhythmias and sudden cardiac death in diabetes mellitus patients. In recent studies, significant changes in repolarizing K+ currents, Na+ currents and L-type Ca2+ currents along with impaired Ca2+ homeostasis and defective contractile function have been identified in the diabetic heart. In addition, insulin levels and other trophic factors change significantly to maintain the ionic channel expression in diabetic patients. There are many diagnostic tools and management options for DCM, but it is difficult to detect its development and to effectively prevent its progress. In this review, diabetes-associated alterations in voltage-sensitive cardiac ion channels are comprehensively assessed to understand their potential role in the pathophysiology and pathogenesis of DCM.
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Affiliation(s)
- Nihal Ozturk
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Serkan Uslu
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
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7
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Abstract
Kv7 channels (Kv7.1-7.5) are voltage-gated K+ channels that can be modulated by five β-subunits (KCNE1-5). Kv7.1-KCNE1 channels produce the slow-delayed rectifying K+ current, IKs, which is important during the repolarization phase of the cardiac action potential. Kv7.2-7.5 are predominantly neuronally expressed and constitute the muscarinic M-current and control the resting membrane potential in neurons. Kv7.1 produces drastically different currents as a result of modulation by KCNE subunits. This flexibility allows the Kv7.1 channel to have many roles depending on location and assembly partners. The pharmacological sensitivity of Kv7.1 channels differs from that of Kv7.2-7.5 and is largely dependent upon the number of β-subunits present in the channel complex. As a result, the development of pharmaceuticals targeting Kv7.1 is problematic. This review discusses the roles and the mechanisms by which different signaling pathways affect Kv7.1 and KCNE channels and could potentially provide different ways of targeting the channel.
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Affiliation(s)
- Emely Thompson
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - Jodene Eldstrom
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - David Fedida
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
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8
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Jensen MT. Resting heart rate and relation to disease and longevity: past, present and future. Scandinavian Journal of Clinical and Laboratory Investigation 2019; 79:108-116. [PMID: 30761923 DOI: 10.1080/00365513.2019.1566567] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Assessment of heart rate has been used for millennia as a marker of health. Several studies have indicated that low resting heart rate (RHR) is associated with health and longevity, and conversely, a high resting heart to be associated with disease and adverse events. Longitudinal studies have shown a clear association between increase in heart rate over time and adverse events. RHR is a fundamental clinical characteristic and several trials have assessed the effectiveness of heart rate lowering medication, for instance beta-blockers and selective sinus node inhibition. Advances in technology have provided new insights into genetic factors related to RHR as well as insights into whether elevated RHR is a risk factor or risk marker. Recent animal research has suggested that heart rate lowering with sinus node inhibition is associated with increased lifespan. Furthermore, genome-wide association studies in the general population using Mendelian randomization have demonstrated a causal link between heart rate at rest and longevity. Furthermore, the development in personal digital devices such as mobile phones, fitness trackers and eHealth applications has made heart rate information and knowledge in this field as important as ever for the public as well as the clinicians. It should therefore be expected that clinicians and health care providers will be met by relevant questions and need of advice regarding heart rate information from patients and the public. The present review provides an overview of the current knowledge in the field of heart rate and health.
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Affiliation(s)
- Magnus T Jensen
- a Department of Cardiology , Rigshospitalet , Copenhagen, Denmark.,b Department of Cardiology , Herlev-Gentofte Hospital , Hellerup , Denmark
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9
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Isaksen JL, Graff C, Ellervik C, Jensen JS, Rossing P, Kanters JK, Jensen MT. Cardiac repolarization and depolarization in people with Type 1 diabetes with normal ejection fraction and without known heart disease: a case-control study. Diabet Med 2018; 35:1337-1344. [PMID: 29797352 DOI: 10.1111/dme.13689] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 10/16/2022]
Abstract
AIMS To investigate depolarization and repolarization durations in people with Type 1 diabetes, including the relationship to age. METHODS 855 persons with Type 1 diabetes without known heart disease were included and matched with 1710 participants from a general population study. Clinical examinations, questionnaires and biochemistry were assessed. A 10-second 12-lead ECG was performed and analysed digitally. RESULTS QTc was longer in people with Type 1 diabetes compared to controls (414±16 vs. 411±19 ms, P <0.001), and particularly so in young people with Type 1 diabetes. The fully adjusted increase was 13.8 ms (95% confidence interval (CI): 8.6-19.0 ms, P <0.001) at age 20 years and 3.4 ms (CI: 1.5-5.3 ms, P<0.001) at age 40 years. The rate-corrected QRSc was increased in people with Type 1 diabetes (97±11 vs. 95±11 ms, P <0.001) and was age-independent (P =0.5). JTc was increased in the young people with Type 1 diabetes (10.7 ms (CI: 5.4-16.0 ms, P <0.001) at age 20 years), but not in older people with Type 1 diabetes (interaction age-diabetes, P <0.01). CONCLUSIONS For people with Type 1 diabetes, cardiac depolarization is increased at all ages, whereas repolarization is increased only relatively in young people with Type 1 diabetes. Hence, young people with Type 1 diabetes may be more prone to ventricular arrhythmias. The findings contribute to the understanding of sudden cardiac death in young people with Type 1 diabetes.
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Affiliation(s)
- J L Isaksen
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - C Graff
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - C Ellervik
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - J S Jensen
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Cardiology S, Herlev and Gentofte University Hospital, Copenhagen, Denmark
| | - P Rossing
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Aarhus University, Aarhus, Denmark
| | - J K Kanters
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M T Jensen
- Department of Cardiology S, Herlev and Gentofte University Hospital, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- The Heart Centre, Rigshospitalet, Copenhagen, Denmark
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10
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Abraham MB, Jones TW, Naranjo D, Karges B, Oduwole A, Tauschmann M, Maahs DM. ISPAD Clinical Practice Consensus Guidelines 2018: Assessment and management of hypoglycemia in children and adolescents with diabetes. Pediatr Diabetes 2018; 19 Suppl 27:178-192. [PMID: 29869358 DOI: 10.1111/pedi.12698] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 05/28/2018] [Indexed: 12/23/2022] Open
Affiliation(s)
- Mary B Abraham
- Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Australia.,Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia.,Division of Paediatrics, Medical School, The University of Western Australia, Perth, Australia
| | - Timothy W Jones
- Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Australia.,Children's Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia.,Division of Paediatrics, Medical School, The University of Western Australia, Perth, Australia
| | - Diana Naranjo
- Division of Endocrinology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Beate Karges
- Division of Endocrinology and Diabetes, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | | | - Martin Tauschmann
- Wellcome Trust-MRC Institute of Metabolic Science, Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - David M Maahs
- Division of Endocrinology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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11
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Anagandula M, Richardson SJ, Oberste MS, Sioofy-Khojine AB, Hyöty H, Morgan NG, Korsgren O, Frisk G. Infection of human islets of Langerhans with two strains of Coxsackie B virus serotype 1: assessment of virus replication, degree of cell death and induction of genes involved in the innate immunity pathway. J Med Virol 2013; 86:1402-11. [PMID: 24249667 DOI: 10.1002/jmv.23835] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2013] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes mellitus is believed to be triggered, in part, by one or more environmental factors and human enteroviruses (HEVs) are among the candidates. Therefore, this study has examined whether two strains of HEV may differentially affect the induction of genes involved in pathways leading to the synthesis of islet hormones, chemokines and cytokines in isolated, highly purified, human islets. Isolated, purified human pancreatic islets were infected with strains of Coxsackievirus B1.Viral replication and the degree of CPE/islet dissociation were monitored. The expression of insulin, glucagon, CXCL10, TLR3, IF1H1, CCL5, OAS-1, IFNβ, and DDX58 was analyzed. Both strains replicated in islets but only one of strain caused rapid islet dissociation/CPE. Expression of the insulin gene was reduced during infection of islets with either viral strain but the gene encoding glucagon was unaffected. All genes analyzed which are involved in viral sensing and the development of innate immunity were induced by Coxsackie B viruses, with the notable exception of TLR3. There was no qualitative difference in the expression pattern between each strain but the magnitude of the response varied between donors. The lack of virus induced expression of TLR3, together with the differential regulation of IF1H1, OAS1 and IFNβ, (each of which has polymorphic variants influence the predisposition to type 1 diabetes), that might result in defective clearance of virus from islet cells. The reduced expression of the insulin gene and the unaffected expression of the gene encoding glucagon by Coxsackie B1 infection is consistent with the preferential β-cell tropism of the virus.
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Affiliation(s)
- Mahesh Anagandula
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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12
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Kavak S. Effects of Insulin on Altered Mechanical and Electrical Papillary Muscle Activities of Diabetic Rats. J Membr Biol 2012; 246:31-7. [DOI: 10.1007/s00232-012-9499-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 08/18/2012] [Indexed: 10/27/2022]
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13
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Hreiche R, Plante I, David LP, Simard C, Turgeon J, Drolet B. Impact of glucose concentration on cardiac ventricular repolarization under IKr/IKs blocking agents. J Mol Cell Cardiol 2009; 47:210-20. [DOI: 10.1016/j.yjmcc.2009.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/21/2009] [Accepted: 02/05/2009] [Indexed: 12/12/2022]
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14
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Abstract
BACKGROUND QT interval shortens with exercise. Some of this shortening is due to an increase in heart rate, and some is due to other effects of exercise, probably mostly neuroendocrine effects. Data from subjects with cardiac transplants have suggested that non-heart rate-related changes in QT interval on exercise are due to the effects of circulating catecholamines. HYPOTHESIS We sought to determine whether changes in plasma catecholamine levels with exercise are an important contributor to non-heart rate-related QT interval shortening. METHODS Subjects with DDD pacemakers were recruited. Subjects had QT intervals measured at rest, during a low fixed level exercise test designed to increase heart rate to about 110 beats/min, and, after resting, during pacing at a heart rate of 110 beats/min. Catecholamine levels were measured at each stage of the study. RESULTS QT interval at rest was 420 +/- 12 ms, during pacing 366 +/- 16 ms, and on exercise 325 +/- 14 ms. This then gave the proportion of QT interval shortening due to heart rate as 68.6 +/- 9.3% of total QT shortening, with the range between 35 and 95.6%. There was no proportionality between the degree of QT interval shortening on exercise that was not due to increases in heart rate and changes in plasma catecholamine levels. CONCLUSION Two-thirds of exercise-induced QT interval shortening are due to an increase in heart rate, and one-third to other effects. Changes in plasma catecholamine levels on exercise were not closely related to changes in the QT interval on exercise.
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Affiliation(s)
- P Davey
- Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
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15
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Tu E, Twigg SM, Semsarian C. Sudden death in type 1 diabetes: the mystery of the 'dead in bed' syndrome. Int J Cardiol 2008; 138:91-3. [PMID: 18676043 DOI: 10.1016/j.ijcard.2008.06.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 06/03/2008] [Indexed: 01/11/2023]
Abstract
Sudden cardiac death is an unpredictable and devastating event, particularly in the young. A significant proportion of sudden deaths in the young are unexplained-no cause is identified either during life or at post-mortem. This is seen in a subgroup of young patients with type 1 diabetes who have dead in bed syndrome, where these victims are in good health, retire to bed, only to be found dead the following morning in a bed which is undisturbed, suggesting no terminal struggle or seizure. The underlying cause of dead in bed syndrome remains unknown, but is likely to be due to a terminal malignant arrhythmia. A plausible hypothesis is that it may be secondary to QT interval prolongation (followed by a degenerate ventricular tachycardia), caused by a number of factors including acute hypoglycaemia, on a background of cardiac autonomic neuropathy, and possible genetic influences. It is envisaged that understanding the causes and triggers of dead in bed syndrome will allow appropriate therapeutic interventions to be initiated in high-risk patients with type 1 diabetes, with the ultimate goal to prevent sudden death.
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16
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Lengyel C, Virág L, Kovács PP, Kristóf A, Pacher P, Kocsis E, Koltay ZM, Nánási PP, Tóth M, Kecskeméti V, Papp JG, Varró A, Jost N. Role of slow delayed rectifier K+-current in QT prolongation in the alloxan-induced diabetic rabbit heart. Acta Physiol (Oxf) 2008; 192:359-68. [PMID: 17970826 DOI: 10.1111/j.1748-1716.2007.01753.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIM In diabetes mellitus, several cardiac electrophysiological parameters are known to be affected. In rodent experimental diabetes models, changes in these parameters were reported, but only limited relevant information is available in other species, having cardiac electrophysiological properties more resembling the human, including the rabbit. The present study was designed to analyse the effects of experimental type 1 diabetes on ventricular repolarization and the underlying transmembrane potassium currents in rabbit hearts. METHODS Diabetes was induced by a single injection of alloxan (145 mg kg(-1) i.v.). After the development of diabetes (3 weeks), electrophysiological studies were performed using whole cell voltage clamp and ECG measurements. RESULTS The QT(c) interval in diabetic rabbits was moderately but statistically significantly longer than measured in the control animals (155 +/- 1.8 ms vs. 145 +/- 2.8 ms, respectively, n = 9-10, P < 0.05). This QT(c)-lengthening effect of diabetes was accompanied by a significant reduction in the density of the slow delayed rectifier K(+) current, I(Ks) (from 1.48 +/- 0.35 to 0.86 +/- 0.17 pA pF(-1) at +50 mV, n = 19-21, P < 0.05) without changes in current kinetics. No differences were observed either in the density or in the kinetics of the inward rectifier K(+) current (I(K1)), the rapid delayed rectifier K(+) current (I(Kr)), the transient outward current (I(to)) and the L-type calcium current (I(CaL)) between the control and alloxan-treated rabbits. CONCLUSION It is concluded that type 1 diabetes mellitus, although only moderately, lengthens ventricular repolarization. Diabetes attenuates the repolarization reserve by decreasing the density of I(Ks) current, and thereby may enhance the risk of sudden cardiac death.
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Affiliation(s)
- Cs Lengyel
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
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17
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Warda M, Kim HK, Kim N, Youm JB, Kang SH, Park WS, Khoa TM, Kim YH, Han J. Simulated hyperglycemia in rat cardiomyocytes: A proteomics approach for improved analysis of cellular alterations. Proteomics 2007; 7:2570-90. [PMID: 17647226 DOI: 10.1002/pmic.200700168] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Diabetic hyperglycemia can lead to stress-related cellular apoptosis of cardiac tissue. However, the mechanism by which hyperglycemia inflicts this damage on the structure and function of the heart is unclear. In this study, we examined the relationship between proteome alterations, mitochondrial function, and major biochemical and electrophysiological changes affecting cardiac performance during simulated short-term hyperglycemia. Two-dimensional comparative proteomics analysis of rat hearts perfused with glucose at high (30 mM) or control (5.5 mM) levels revealed that glucose loading alters cardiomyocyte proteomes. It increased expression levels of initial enzymes of the tricarboxylic acid cycle, and of enzymes of fatty acid beta-oxidation, with consequent up-regulation of enzymes of mitochondrial electron transport. It also markedly decreased expression of enzymes of glycolysis and the final steps of the tricarboxylic acid cycle. Glucose loading increased the rate of Bax-independent apoptosis. High glucose increased the duration of the action potential and elevated level of intracellular cytoplasmic calcium. Surprisingly, glucose loading did not influence levels of nitric oxide or mitochondrial superoxide in isolated cardiomyocytes. In summary, short-term simulated hyperglycemia attenuated expression of many anti-apoptotic proteins. This effect was apparently mediated via alterations in multiple biochemical pathways that collectively increased apoptotic susceptibility.
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Affiliation(s)
- Mohamad Warda
- Department of Physiology and Biophysics, College of Medicine, Biohealth Products Research Center, Cardiovascular and Metabolic Disease Center, FIRST Mitochondrial Research Group, Inje University, Busan, Korea
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18
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Paterson AD, Rutledge BN, Cleary PA, Lachin JM, Crow RS. The effect of intensive diabetes treatment on resting heart rate in type 1 diabetes: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study. Diabetes Care 2007; 30:2107-12. [PMID: 17468351 PMCID: PMC2654598 DOI: 10.2337/dc06-1441] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Cardiovascular disease is a major cause of morbidity and mortality in individuals with type 1 diabetes. Resting heart rate (RHR) is a risk factor for cardiovascular disease in the general population, and case-control studies have reported a higher RHR in individuals with type 1 diabetes. In individuals with type 1 diabetes, there is a positive correlation between A1C and RHR; however, no prospective studies have examined whether a causal relationship exists between A1C and RHR. We hypothesized that intensive diabetes treatment aimed to achieve normal A1C levels has an effect on RHR in individuals with type 1 diabetes. RESEARCH DESIGN AND METHODS A total of 1,441 individuals with type 1 diabetes who participated in the Diabetes Control and Complications Trial (DCCT) had their RHR measured biennially by an electrocardiogram during the DCCT and annually for 10 years during the Epidemiology of Diabetes Interventions and Complications (EDIC) follow-up study. RESULTS During the DCCT, intensive treatment was associated with lower mean RHR than conventional treatment, both in adolescents (69.0 vs. 72.0 bpm [95% CI 62.8-75.7 and 65.7-78.9, respectively], P = 0.013) and adults (66.8 vs. 68.2 [65.3-68.4 and 66.6-69.8, respectively], P = 0.0014). During follow-up in the EDIC, the difference in RHR between the treatment groups persisted for at least 10 years (P < 0.0001). CONCLUSIONS Compared with conventional therapy, intensive diabetes management is associated with lower RHR in type 1 diabetes. The lower RHR with intensive therapy may explain, in part, its effect in reducing cardiovascular disease, recently demonstrated in type 1 diabetes.
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Affiliation(s)
- Andrew D Paterson
- Program in Genetics and Genomic Biology, The Hospital for Sick Children, TMDT Building East Tower, Room 15-707, 101 College St., Toronto, ON M5G 1L7, Canada.
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19
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Grandinetti A, Seifried SE, Chow DC, Theriault AG, Mor JM, Schatz IJ, Low PA. Association between angiotensin-converting enzyme gene polymorphisms and QT duration in a multiethnic population in Hawaii. Auton Neurosci 2007; 130:51-6. [PMID: 16769256 DOI: 10.1016/j.autneu.2006.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 01/06/2006] [Accepted: 03/29/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVES Recent studies have suggested that heart-rate corrected QT interval (QTc) in normal populations may be influenced by genetic factors. We report findings of a study of the relationship between QTc, increased QTc (> 440 ms) and angiotensin-converting enzyme (ACE) genotype in a multiethnic, population-based study completed in rural Hawaii. METHODS Blood samples were obtained while fasting and after an oral glucose challenge from 1452 individuals between 1997 and 2000. The clinical examination included an electrocardiogram. Medical histories, behavioral and socio-demographic information were obtained during the interview. Ethnicity was estimated by self-report. The insertion/deletion (I/D) polymorphism in intron 16 of the ACE gene was determined by polymerase chain reaction (PCR) from a random sample of 588 participants. Multiple linear and logistic regression was used to test for associations between QTc and ACE gene polymorphisms. RESULTS The overall crude prevalence of increased QTc was 21.2%. The prevalence of increased QTc was lowest among those with ACE DD genotype, and highest among those with ACE insertion/insertion (II) genotype. The adjusted odds ratio for increased QTc was 2.29 (95% CI 1.02-5.12) and 3.61 (95% CI 1.60-8.13) for ID and II genotypes, respectively, compared to the DD genotype. The test for trend was highly significant (p < 0.001). CONCLUSIONS The ACE insertion allele was associated with increased prevalence of prolonged QTc independent of ethnicity, age, gender, and BMI. These findings may implicate the ACE gene as an important genetic risk factor for cardiovascular disease morbidity and mortality.
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Affiliation(s)
- Andrew Grandinetti
- University of Hawaii at Manoa, John A. Burns School of Medicine, Department of Public Health and Epidemiology, Honolulu, Hawaii 96822, USA.
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20
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Grandinetti A, Seifried S, Mor J, Chang HK, Theriault AG. Prevalence and risk factors for prolonged QTc in a multiethnic cohort in rural Hawaii. Clin Biochem 2005; 38:116-22. [PMID: 15642272 DOI: 10.1016/j.clinbiochem.2004.10.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 10/15/2004] [Accepted: 10/20/2004] [Indexed: 11/17/2022]
Abstract
BACKGROUND Few studies have examined the biochemical risk factors for prolonged QTc, a predictor of mortality in numerous studies. We report on the prevalence and risk factors for prolonged QTc in a multiethnic population in rural Hawaii. METHODS Electrocardiograms were collected from 1415 participants in a cross-sectional survey. The QT interval lengths were corrected for heart rate using Bazett's formula. Linear and logistic regression models were used to examine associations between various cardiovascular risk factors with QTc. RESULTS Among the CVD risk factors examined, only age, gender, 2-h glucose, and systolic blood pressure (SBP) were independently associated with QTc interval length. Significant ethnic differences in prevalence were also observed, which persisted after controlling for other risk factors. CONCLUSIONS Significant associations between prolonged QTc and ethnic ancestry, but not cholesterol or triglyceride levels, suggest that genetic factors may play a more important role in determining QTc interval length than conventional biochemical and metabolic CVD risk factors.
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Affiliation(s)
- Andrew Grandinetti
- University of Hawaii at Manoa, Pacific Biomedical Research Center, 1993 East-West Road, Honolulu, Honolulu, HI 96822, USA.
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21
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Koçer A, Aktürk Z, Maden E, Taşçı A. Orthostatic Hypotension and Heart Rate Variability as Signs of Cardiac Autonomic Neuropathy in Diabetes Mellitus. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2005. [DOI: 10.29333/ejgm/82257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Pietilä E, Fodstad H, Niskasaari E, Laitinen P PJ, Swan H, Savolainen M, Kesäniemi YA, Kontula K, Huikuri HV. Association between HERG K897T polymorphism and QT interval in middle-aged Finnish women. J Am Coll Cardiol 2002; 40:511-4. [PMID: 12142119 DOI: 10.1016/s0735-1097(02)01979-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES The aim of this study was to test whether a recently reported polymorphism in the HERG gene coding for the rapidly activating delayed rectifier K+ channel has influence on myocardial repolarization. BACKGROUND The length of myocardial repolarization, measured as the QT interval, has a hereditary component, but no genes that would explain the variability of repolarization have been identified in healthy subjects. METHODS QT intervals were measured from the 12-lead electrocardiogram in a random middle-aged population (226 men/187 women). The longest QT interval at any of the 12 leads (QTmax), QTV(2), and the Tpeak-Tend interval were used as measures of repolarization. Deoxyribonucleic acid samples were genotyped for the nucleotide 2690A>C variation of the HERG gene, corresponding to the HERG K(lysine)897T(threonine) amino acid polymorphism. RESULTS The allele frequencies were 0.84 (A) and 0.16 (C). Females with the genotype AC or CC had longer QTcmax (477 +/- 99 ms) and Tpeak-Tend intervals (143 +/- 95 ms) than females with the genotype AA (441 +/- 69 ms and 116 +/- 65 ms, p = 0.005 and p = 0.025, respectively). In males, the QTcmax and the Tpeak-Tend intervals did not differ between the genotypes. After adjustment for echocardiographic and various laboratory variables, the HERG K897T polymorphism remained as an independent predictor of QTcmax (p = 0.009) and the Tpeak-Tend intervals (p = 0.026) in females. CONCLUSIONS; The common K897T polymorphism of the HERG channel is associated with the maximal duration and transmural dispersion of ventricular repolarization in middle-aged females.
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Affiliation(s)
- Eeva Pietilä
- Division of Cardiology, Department of Medicine, University of Oulu, Oulu, Finland
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23
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Deguchi K, Sasaki I, Tsukaguchi M, Kamoda M, Touge T, Takeuchi H, Kuriyama S. Abnormalities of rate-corrected QT intervals in Parkinson's disease-a comparison with multiple system atrophy and progressive supranuclear palsy. J Neurol Sci 2002; 199:31-7. [PMID: 12084439 DOI: 10.1016/s0022-510x(02)00079-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A number of patients with Parkinson's disease (PD) and multiple system atrophy (MSA), in whom sudden death does occur occasionally, have QT or rate-corrected QT (QTc) interval prolongation on electrocardiogram (ECG). Although these QT or QTc interval abnormalities are likely related to autonomic dysfunction, the pathophysiology remains unknown. The aim of this study was to compare the degree of QTc interval prolongation among akinetic-rigid syndromes, namely PD and related disorders, and to evaluate the relationship between QTc prolongation and severity of autonomic dysfunction. Thirty-four patients with PD, 22 with MSA, 11 with progressive supranuclear palsy (PSP) and 30 healthy controls underwent standard autonomic function tests, and electrocardiography variables (RR, QT and QTc intervals) were measured by an ECG recorder with an automated analyzer. The relationship between QTc interval and cardiovascular reflex tests were also analyzed. Orthostatic hypotension and decreased heart rate in response to respiratory stimuli were prominent in MSA, while these were relatively mild in PD. Unlike the RR and QT intervals, the QTc interval significantly differed among all groups (p<0.01). The QTc interval was significantly prolonged in PD (409+/-17 ms; p<0.001) and MSA (404+/-14 ms; p<0.05) compared with healthy controls (394+/-19 ms). Neither autonomic dysfunction nor QTc interval prolongation was evident in PSP. QTc intervals and cardiovascular reflexes did not correlate, except for Valsalva ratio. The QTc interval was obviously prolonged in PD patients to an extent that could not be accounted for simply by autonomic dysfunction levels. MSA patients showed slightly prolonged QTc intervals in spite of marked cardiovascular autonomic dysfunction. Abnormalities of the QTc may reflect the degeneration of cardioselective sympathetic and parasympathetic neurons that cannot be fully captured by cardiovascular autonomic function tests.
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Affiliation(s)
- Kazushi Deguchi
- Third Department of Internal Medicine, Kagawa Medical University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan
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24
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Shimoni Y. Inhibition of the formation or action of angiotensin II reverses attenuated K+ currents in type 1 and type 2 diabetes. J Physiol 2001; 537:83-92. [PMID: 11711563 PMCID: PMC2278945 DOI: 10.1111/j.1469-7793.2001.0083k.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
1. Transient and sustained calcium-independent outward K(+) currents (I(t) and I(SS)) as well as action potentials were recorded in cardiac ventricular myocytes isolated from two models of diabetes mellitus. 2. Rats injected (I.V.) with streptozotocin (STZ, 100 mg kg(-1)) 6-10 days before cell isolation developed insulin-dependent (type 1) diabetes. I(t) and I(SS) were attenuated and the action potential prolonged. Incubation of myocytes (6-9 h) with the angiotensin II (ATII) receptor blockers saralasin or valsartan (1 microM) significantly augmented these currents. Inclusion of valsartan (1 g l(-1)) in the drinking water for 5-10 days prior to and following STZ injection partially prevented current attenuation. 3. Incubation of myocytes from STZ-treated rats (6-9 h) with 1 microM quinapril, an angiotensin-converting enzyme (ACE) inhibitor, significantly augmented I(t) and I(SS) and shortened the ventricular action potential. I(t) augmentation was not due to changes in steady-state inactivation or in recovery from inactivation. No acute effects of quinapril were observed. 4. The effects of quinapril and valsartan were abolished by 2 microM cycloheximide. 5. Myocytes were isolated from the db/db mouse, a leptin receptor mutant that develops symptoms of non-insulin-dependent (type 2) diabetes. K+ currents in these cells were also attenuated, and the action potentials prolonged. Incubation of these cells (> 6 h) with valsartan (1 microM) significantly enhanced the transient and sustained outward currents. 6. These results confirm recent suggestions that cardiac myocytes contain a renin-angiotensin system, which is activated in diabetes. It is proposed that chronic release of ATII leads to changes in ionic currents and action potentials, which can be reversed by blocking the formation or action of ATII. This may underlie the proven benefits of ATII receptor blockade or ACE inhibition in diabetes, by providing protection against cardiac arrhythmias.
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Affiliation(s)
- Y Shimoni
- Department of Physiology and Biophysics, Cardiovascular Research Group, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1.
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25
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Hong Y, Rautaharju PM, Hopkins PN, Arnett DK, Djoussé L, Pankow JS, Sholinsky P, Rao DC, Province MA. Familial aggregation of QT-interval variability in a general population: results from the NHLBI Family Heart Study. Clin Genet 2001; 59:171-7. [PMID: 11260226 DOI: 10.1034/j.1399-0004.2001.590305.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
QT-interval prolongation is associated with increased risk of cardiac death. Although information on genetics and molecular mechanisms of the congenital long QT syndrome is mounting, limited data are available on the genetics of QT interval in the general population. Heart rate adjusted QT intervals (Bazett's QTc, and QT index (QTI)) were assessed by electrocardiography in 2399 members aged 25-91 years of 468 randomly selected families participating in the NHLBI Family Heart Study. Familial correlation and segregation analyses were performed to evaluate the genetics of the variability of QT interval in this population. The parent-offspring (0.14+/-0.03) and sibling (0.18+/-0.03) correlations for age and sex-adjusted QTc were moderate, while the spouse correlation was close to zero (0.09+/-0.06). This suggests that there are familial/genetic influences on QT-interval variability. Segregation analysis results suggest that there is a major effect in addition to heritable multifactorial effects (h2=0.34), but the major effect did not follow Mendelian inheritance. Further adjustments of QTc for other major cardiovascular risk factors did not significantly change the results. Similar results were found for QTI. The QT-interval variation in the general population is influenced by moderate heritable multifactorial effects in addition to a major effect. A major gene effect is not directly supported.
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Affiliation(s)
- Y Hong
- Division of Biostatistics, Washington University, St Louis, MO 63110, USA
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26
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Earle KA, Mishra B, Morocutti A, Barnes D, Chambers J, Viberti GC. QT dispersion in microalbuminuric Type 1 diabetic patients without myocardial ischemia. J Diabetes Complications 2000; 14:277-80. [PMID: 11113691 DOI: 10.1016/s1056-8727(00)00123-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Microalbuminuria is associated with an increased risk of cardiac death. We assessed whether urinary albumin excretion is related to abnormalities of the QT interval independently of myocardial ischemia. Thirty-four patients with type 1 diabetes who were free from ischemic heart disease on the basis of normal stress electrocardiography and echocardiography were studied. Maximal QT interval and dispersion were significantly greater in the group with microalbuminuria (n=17) compared to controls (n=17) with normal urinary albumin excretion (394 [26.1] vs. 373.8 [27.8] ms; P=.044 and 62.4 [21.8] vs. 42.7[11.6] arbitrary units; P=.009). Autonomic function was similar between the groups. Urinary albumin excretion correlated positively with QT dispersion (P=.023). These data suggest that in type 1 diabetic patients, QT abnormalities can occur independently of autonomic dysfunction or myocardial ischemia and may be related to the processes which increase urinary albumin leakage.
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Affiliation(s)
- K A Earle
- Department of Diabetes and Endocrinology, Guy's, Kings and St. Thomas' Medical School, SE1 7EH, London, UK.
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27
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Abstract
Abnormalities in the QT interval can be divided into 3 types, prolongation of the QT interval, increases in the dispersion of the QT interval, and abnormalities in the heart rate dependent behavior of the QT interval. Abnormalities may be found in short or long-term recordings. Prolongation of the QT interval may reflect factors associated with an adverse prognosis in coronary disease and may in itself be arrhythmogenic. The data to date suggest that there is an association between adverse prognosis and QT interval prolongation in coronary disease, both before and after acute myocardial infarctions. This relationship is weak, however, and is not clinically useful. The data as to whether increased QT dispersion postmyocardial infarction relates to adverse prognosis is weak because there is no convincing evidence yet. If there is a relationship it is weak. Abnormalities in the rate dependent behavior of the QT interval are widely found, but as no large scale prospective study with mortality as an endpoint has yet been undertaken the significance of rate dependent abnormalities is uncertain. The widespread introduction of beat-to-beat QT analysis of 24 hour Holter tapes may take QT intervalology into the realm of clinical practice.
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Affiliation(s)
- P Davey
- Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom
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28
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Friedlander Y, Lapidos T, Sinnreich R, Kark JD. Genetic and environmental sources of QT interval variability in Israeli families: the kibbutz settlements family study. Clin Genet 1999; 56:200-9. [PMID: 10563479 DOI: 10.1034/j.1399-0004.1999.560304.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
QT interval prolongation not attributed to long QT syndromes is reported to be associated with increased risk of sudden and nonsudden cardiac death. Genetic and environmental determinants of QTc interval were investigated in an unselected free living population sample of 80 kindreds residing in kibbutz settlements in Israel. The sample included 214 males and 227 females aged 15-97 years. There was a significant familial aggregation of adjusted QT interval levels, as indicated by inter- and intraclass correlation coefficients significantly different from zero. Complex segregation analysis applied to the sex- and age-adjusted data was not conclusive and heterogeneous etiologies for individual differences were suggested. There was evidence for a single recessive locus (q = 0.173) with a major effect in addition to polygenic effects (h2 = 0.41) that explained the mixture of distributions. In parallel, a nontransmitted environmental major factor in addition to polygenic effects that explained the adjusted variation in QTc could not be rejected. Similar results were obtained upon the adjustment for sex, age, and environmental covariables. The major factor, either genetic or environmental, and polygenic-loci accounted for about 20 and 33% of the adjusted QTc variation, respectively. Furthermore, sex, age, measured environmental covariables, the unmeasured major factor, and the unmeasured polygenes could account for 63% of the variation of QTc in these families. Our data provide evidence for a major factor, either genetic or environmental, in addition to a polygenic background, influencing QT interval levels in a population-based sample of pedigrees.
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Affiliation(s)
- Y Friedlander
- Department of Social Medicine, The Hebrew University-Hadassah School of Public Health, Jerusalem, Israel.
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29
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Shimoni Y. Hormonal control of cardiac ion channels and transporters. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1999; 72:67-108. [PMID: 10446502 DOI: 10.1016/s0079-6107(99)00005-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Y Shimoni
- Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Alta., Canada.
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30
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Harris ND, Heller SR. Sudden death in young patients with Type 1 diabetes: a consequence of disease, treatment or both? Diabet Med 1999; 16:623-5. [PMID: 10477205 DOI: 10.1046/j.1464-5491.1999.00046.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Whitsel EA, Boyko EJ, Siscovick DS. Accuracy of QTcand QTI for Detection of Autonomic Dysfunction. Ann Noninvasive Electrocardiol 1999. [DOI: 10.1111/j.1542-474x.1999.tb00209.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Pacher P, Ungvári Z, Nánási PP, Kecskeméti V. Electrophysiological changes in rat ventricular and atrial myocardium at different stages of experimental diabetes. ACTA PHYSIOLOGICA SCANDINAVICA 1999; 166:7-13. [PMID: 10372973 DOI: 10.1046/j.1365-201x.1999.00538.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Action potential configuration in ventricular and atrial myocardium, as well as rate-dependent changes in ventricular action potential duration (APD) were studied and compared in healthy and diabetic rats. Diabetes was induced by a single injection of streptozotocin (STZ, 65 mg kg(-1) i.v.). Conventional microelectrode techniques were applied to record action potentials after the establishment of diabetes (2, 6, 10 and 18 weeks after STZ-treatment). Untreated age-matched animals were used as controls. Both depolarization and repolarization were significantly retarded following STZ-treatment. However, the time course of development of diabetic changes in atrial and ventricular myocardium was different. APD was significantly lengthened from week 2 of diabetes in ventricular, but only from week 6 in atrial preparations. In atrial myocardium, lengthening of APD was more pronounced at early rather than late phases of repolarization. The maximum rate of depolarization (Vmax) was significantly reduced from the 6th week of diabetes in both preparations. No differences were observed in action potential amplitude (except at week 18) and in the resting membrane potential in diabetic rats. Diabetic ventricular preparations showed a positive APD-frequency relationship at any level of repolarization, in contrast to control muscles, where APD25 and APD50 values lengthened. But APD75 and APD90 values were not changed significantly with increase in the pacing frequency. The results indicate that development of diabetic alterations are not fully identical in atrial and ventricular myocardium of the rat, probably owing to differences in density and kinetics of ionic currents responsible for atrial and ventricular action potentials.
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Affiliation(s)
- P Pacher
- Department of Pharmacology, Semmelweis University of Medicine, Budapest, Hungary
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Katsuoka H, Mimori Y, Kurokawa K, Harada T, Kohriyama T, Ishizaki F, Harada A, Nakamura S. QTc interval, and autonomic and somatic nerve function in diabetic neuropathy. Clin Auton Res 1998; 8:139-43. [PMID: 9651663 DOI: 10.1007/bf02281118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
QTc intervals were measured using an electrocardiogram and other autonomic function tests, in 66 neuropathy patients with non-insulin-dependent diabetes mellitus (59.0 +/- 12.5 years; mean +/- SD). The change in R-R interval did not influence the QTc interval, as calculated by the equation: QTc = QT + (1000 - R-R)/7 (ms), compared with the conventional Bazett's equation which appeared to overcompensate in the case of a small R-R interval. The QTc interval in the diabetic patients was significantly longer than that in age-matched controls. The QTc interval showed an inverse correlation with the coefficient of variation of the R-R interval and skin blood flow at rest. However, no correlation was found between QTc interval and blood pressure change, change in heart rate on standing, or results of the sympathetic skin response. The QTc interval did not correlate significantly with motor or sensory nerve conduction parameters. We conclude that the QTc interval can be a simple and useful autonomic indicator for diabetic neuropathy relatively independent of other abnormalities of autonomic and somatic nervous system function.
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Affiliation(s)
- H Katsuoka
- Third Department of Internal Medicine, Hiroshima University School of Medicine, Japan
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Shimoni Y, Ewart HS, Severson D. Type I and II models of diabetes produce different modifications of K+ currents in rat heart: role of insulin. J Physiol 1998; 507 ( Pt 2):485-96. [PMID: 9518707 PMCID: PMC2230808 DOI: 10.1111/j.1469-7793.1998.485bt.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. Several K+ currents were measured and compared in enzymatically dispersed ventricular myocytes from control and diabetic rats. 2. Diabetic conditions were established either with a single intravenous injection of streptozotocin (STZ, 100 mg kg-1; 6-14 days duration) or by feeding with a fructose-enriched diet for 4-10 weeks. Both groups became hyperglycaemic, with the former having decreased and the latter having elevated levels of plasma insulin. These conditions therefore mimic type I (insulin-dependent) and type II (non-insulin-dependent) diabetes mellitus, respectively. 3. As reported previously, a Ca(2+)-independent transient outward K+ current, I(t), was attenuated in the type I model. This was not observed in the type II model. The two models differed greatly in the changes observed in a quasi-steady-state K+ current denoted Iss. In the STZ model Iss was substantially attenuated, whereas in the fructose-fed model it was augmented. In both models, the background inwardly rectifying current, IK1, was unchanged. Concomitantly, there was a substantial prolongation of the action potential in the STZ model but not in the fructose-fed model. 4. Incubation of control myocytes with insulin (100 nM) for 5-9 h caused a significant augmentation of Iss, with no effect on I(t) or on IK1. Incubation of myocytes from STZ-diabetic rats with insulin reversed the attenuation of I(t), but not of Iss. 5. The effect of insulin was not blocked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase. However, inhibition of the mitogen-activated protein kinase pathway with PD98059 prevented restoration of I(t). Insulin action on I(t) may therefore involve changes in transcription or expression of channel proteins, rather than changes in cellular metabolism.
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Affiliation(s)
- Y Shimoni
- Department of Physiology and Biophysics, University of Calgary, Alberta, Canada.
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Vanninen E, Unsitupa MI, Länsimies E. Ventricular repolarization is correlated with metabolic control in newly diagnosed type 2 diabetes. CLINICAL PHYSIOLOGY (OXFORD, ENGLAND) 1996; 16:449-61. [PMID: 8842579 DOI: 10.1111/j.1475-097x.1996.tb00732.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Good metabolic control may improve cardiac function in diabetic patients. It is not known, however, whether this functional improvement is associated with concomitant electrocardiographic changes. The aim of the present prospective study was to evaluate the quantitative electrocardiographic and vectorcardiographic correlates of metabolic control, left ventricular function and dimensions, and autonomic nervous function in patients with newly diagnosed Type 2 diabetes. We studied 35 patients (20 men, 15 women; age 52 +/- 6 years (mean +/- SD) with normal electrocardiograms at 1.5 and 15 months after the diagnosis of Type 2 (non-insulin-dependent) diabetes. During the follow-up, body weight decreased, and significant improvement was observed in metabolic control, cardiac function and autonomic nervous function. Concomitantly, maximal spatial vector of T wave increased from 238 +/- 122 to 284 +/- 141 microV (P < 0.01), and this increase was correlated with a decrease in glycosylated haemoglobin A1C (r = -0.45, P < 0.01) and plasma insulin (r = -0.46, P < 0.01). In addition, duration of QRS complex shortened from 94 +/- 9 to 92 +/- 8 ms (P < 0.05), and this shortening was correlated with an increase in heart rate variability (r = -0.34; P < 0.05) and a decrease in peak early to late left ventricular filling flow velocity (r = 0.35, P < 0.05). These changes were most prominent in patients with co-existing hypertension and coronary artery disease. In conclusion, improving metabolic control of diabetes is associated with changes in ventricular repolarization and shortening of QRS complex duration.
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Affiliation(s)
- E Vanninen
- Department of Clinical Physiology, Kuopio University Hospital, Finland
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Lo SS, Mathias CJ, Sutton MS. QT interval and dispersion in primary autonomic failure. HEART (BRITISH CARDIAC SOCIETY) 1996; 75:498-501. [PMID: 8665344 PMCID: PMC484349 DOI: 10.1136/hrt.75.5.498] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To investigate the role of the autonomic nervous system in determining QT interval and dispersion. PATIENTS AND METHODS 32 patients with chronic primary (idiopathic) autonomic failure (19 men, mean age 60 years) and 21 normal controls (11 men, mean age 59) without symptoms of ischaemic heart disease were studied retrospectively. Autonomic failure was diagnosed by a combination of symptomatic postural hypotension, subnormal plasma noradrenaline response to head-up tilt, and abnormal cardiovascular responses to standing, Valsalva manoeuvre, mental stress, cutaneous cold, isometric exercise, and deep breathing. QT intervals were measured from surface electrocardiograms and QT dispersion was defined as maximum QT--minimum QT occurring in any of the 12 leads. RESULTS Mean heart rate (RR intervals) was similar in patients with autonomic failure and controls (S2 lead: 865 (132) v 857 (108) ms, P = NS; V2 lead: 865 (130) v 868 (113) ms, P = NS). QT intervals measured from electrocardiogram leads S2 and V2 were significantly longer in patients than in controls (401 (40) v 376 (16) ms, P < 0.01; and 403 (41) v 381 (20) ms, P < 0.05 respectively). The mean maximum QT interval in any lead, which is the best estimate of the maximum duration of electrical systole, was significantly longer in the patients than in controls (417 (48) v 388 (23) ms, P < 0.005). Linear regression analysis of QT and RR intervals for both groups showed a significant difference between the slopes of the two regression lines (F = 8.4, P < 0.001). However, QT dispersions were similar between patients and controls. CONCLUSIONS Patients with primary autonomic failure have prolongation of QT intervals, indicating that the autonomic nervous system is an important determinant of QT interval. However, QT dispersion does not seem to be affected by chronic primary autonomic denervation.
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Affiliation(s)
- S S Lo
- Department of Cardiology, Royal Brompton Hospital, London
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Frongillo D, Stocchi F, Delfino FA, Calò L, Bramante L, Antonucci F, De Nardo D, Ruggleri S, Cannata D. QT interval and QT dispersion in multiple system atrophy (Shy-Drager syndrome). Clin Auton Res 1996; 6:67-70. [PMID: 8726089 DOI: 10.1007/bf02291225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To evaluate the influence of autonomic function on the QT interval and QT dispersion, 18 patients (10 males and 8 females; mean age 61 +/- 9 years) with multiple system atrophy (MSA, Shy-Drager syndrome) were studied. Cardiovascular tests were performed to assess the degree of autonomic dysfunction. The QT interval, corrected QT (QTc), QT dispersion (QTd), corrected and adjusted QTd were calculated from a standard 12-lead electrocardiogram. Fifteen healthy subjects matched for sex and age were studied as controls. Nine MSA patients showed severe autonomic dysfunction with orthostatic hypotension. In the remaining patients definite autonomic impairment was found. No statistically significant difference was found in QTd and only a trend towards higher values of maximal QTc was found in patients compared with controls. QTc prolongation, defined as greater than the mean +/- 2 SD of the controls, was detected only in three out of the 18 MSA patients (17%). No correlation was found between the severity of autonomic impairment and repolarization parameters. Our data suggest that chronic autonomic impairment in patients with MSA does not significantly affect ventricular repolarization and ventricular dispersion.
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Affiliation(s)
- D Frongillo
- Department of Internal Medicine School of Cardiovascular Diseases, University Tor Vergata, Rome, Italy
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Veglio M, Chinaglia A, Borra M, Perin PC. Does abnormal QT interval prolongation reflect autonomic dysfunction in diabetic patients? QTc interval measure versus standardized tests in diabetic autonomic neuropathy. Diabet Med 1995; 12:302-6. [PMID: 7600743 DOI: 10.1111/j.1464-5491.1995.tb00481.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The question as to whether the QTc interval correlates with five cardiovascular tests (deep breathing test, 30/15 ratio test, lying to standing test, cough test, and postural blood pressure test) for the diagnosis of diabetic autonomic neuropathy (DAN) was investigated in 168 (38 Type 1, 130 Type 2) consecutive outpatients (mean age 54.9 +/- 11.2 years). QT interval was measured on an ECG recorded at rest and QTc calculated according to Bazett's formula. The percentage of patients with a QTc greater than 0.440 s was: absent DAN = 11% (n = 7), probable DAN = 7% (n = 4), definite DAN = 23% (n = 12) (p < 0.05), and the mean (+/- SD) QTc values were 0.403 +/- 0.028 s, 0.405 +/- 0.023 s, and 0.421 +/- 0.026 s, respectively. A significant correlation between QTc duration and DAN score of autonomic cardiovascular test results (r = 0.34, p < 0.0001) was observed. The calculated specificity, sensitivity, positive and negative predictive values were 89%, 15%, 70% and 37%, respectively. In conclusion, QTc can be considered as an additional specific test in the assessment of diabetic autonomic neuropathy, but cannot replace the standard battery of cardiovascular tests.
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Affiliation(s)
- M Veglio
- Department of Internal Medicine, University of Turin, Italy
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Ziegler D. Diabetic cardiovascular autonomic neuropathy: prognosis, diagnosis and treatment. DIABETES/METABOLISM REVIEWS 1994; 10:339-83. [PMID: 7796704 DOI: 10.1002/dmr.5610100403] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- D Ziegler
- Diabetes Research Institute, Heinrich-Heine-University, Düsseldorf, Germany
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Abstract
The electrophysiological properties of single ventricular myocytes from control rats and from rats made diabetic by streptozotocin (STZ) injection (100 mg/kg body weight) have been investigated using whole-cell voltage-clamp measurements. Our major goal was to define the effects of diabetes on rate-dependent changes in action potential duration and the underlying outward K+ currents. As early as 4 to 6 days after STZ treatment, significant elevation of plasma glucose levels occurs, and the action potential duration increases. In both control and diabetic rats, when the stimulation rate is increased, the action potential is prolonged, but this lengthening is considerably more pronounced in myocytes from diabetic rats. In ventricular myocytes from diabetic rats, the Ca(2+)-independent transient outward K+ current (I(t)) is reduced in amplitude, and its reactivation kinetics are slowed. These changes result in a smaller I(t) at physiological heart rates. The steady-state outward K+ current (IK) also exhibits rate-dependent attenuation, and this phenomenon is more pronounced in cells from diabetic rats. These STZ-induced changes in I(t) and IK also develop when a lower dose (55 mg/kg) of STZ is used and measurements are made after 7 weeks of treatment. These electrophysiological effects are not related to the hypothyroid conditions that accompany the diabetic state, since they cannot be reversed by replacement of the hormone L-triiodothyronine to physiological levels. Direct effects of STZ could be ruled out, since preceding the STZ injection with a bolus injection of 3-O-methylglucose, which prevents development of hyperglycemia, prevents the electrophysiological changes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- Y Shimoni
- Department of Medical Physiology, University of Calgary School of Medicine, Alberta, Canada
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